gpiolib: put gpio_suffixes in a single compilation unit

gpiolib: put gpio_suffixes in a single compilation unit

The gpio_suffixes array is defined in the gpiolib.h header. This means
the array is stored in .rodata of every compilation unit that includes
it. Put the definition for the array in gpiolib.c and export just the
symbol in the header. We need the size of the array so expose it too.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20240612184821.58053-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>